Energy calibration of surface barrier detectors for fission fragments

doi:10.1016/0168-9002(86)91041-7

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Volume 248, Issues 2–3, 1 August 1986, Pages 506-515

https://doi.org/10.1016/0168-9002(86)91041-7 Get rights and content

Abstract

The pulseheight, X, delivered in surface barrier detectors by incoming fission fragments of given energy, E, and mass, M, has been studied. Fragments separated as to energy and mass from the ²³⁵U(n, f) reaction induced by thermal neutrons were available from the Lohengrin spectrometer of the ILL. The energies on Lohengrin were calibrated by a time-of-flight technique. It could be shown that for the mass and energy ranges of unslowed fragments encountered in nuclear fission there is a linear relationship between E and X for any fixed M, and similarly a linear relationship holds between E and M for any fixed X. The calibration equation, therefore, reads E = (a + a′M) X + b + b′M with a through b′ being constants characterizing the detector. In parallel to the above measurements, the pulseheight spectra from a ²⁵²Cf(sf) source were taken. The pulseheights X = P_L and X = P_H for the light and heavy fragment peaks of this spectrum were determined by a fitting procedure with Gaussians. Several detectors having been tested, it appears that at least for detectors of the same brand, a universal calibration scheme can be set up which correlates the detector constants a through b′ to the Cf spectrum parameters P_L and P_H. The accuracy of this calibration is sufficient for most practical purposes.

The above calibration method has been put forward and in general use since many years [1]. However, the revised constants of the present investigation yield kinetic energies of fission fragments which are lower by about 1–2%. These energies are in excellent agreement with recent independent measurements of the kinetic energy release in fission.

Along with the calibration the energy resolution of surface barrier detectors has been studied as a function of bias voltage on the detector and mass or energy of incoming ions.

References (19)

J.B. Moulton et al.
Nucl. Instr. and Meth.
(1978)
H. Henschel et al.
Nucl. Instr. and Meth.
(1981)
K. Paasch et al.
Nucl. Instr. and Meth.
(1984)
A. Oed et al.
Nucl. Instr. and Meth.
(1981)
W. Hartmann et al.
Nucl. Instr. and Meth.
(1979)
E.C. Finch et al.
Nucl. Instr. and Meth.
(1985)
H.W. Schmitt et al.
Phys. Rev.
(1965)
H.W. Schmitt et al.
J.H. Neiler et al.
Phys. Rev.
(1966)

There are more references available in the full text version of this article.

Cited by (62)

The FFIS spectrometer for determination of fission fragment mass distribution with the energy–velocity method
2022, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
The FFIS spectrometer (Fission Fragment Identification Spectrometer) for determining independent fission yields has been developed based on the E–v method. By directly measuring the time-of-flight (TOF) and kinetic energy of fission fragments on their flight path, the post-neutron-emission mass yield distributions can be obtained. With the aim of getting the highest possible mass resolution, an axial grid ionization chamber and a TOF measurement system based on microchannel plate (MCP) detectors were designed. The ionization chamber with a silicon nitride entrance window of 100 nm thickness was tested and calibrated with a ²⁵²Cf spontaneous fission source. The intrinsic energy resolution for 1.27 MeV/u ⁶³Cu particles is measured to be 450 keV (FWHM). The time resolution was determined with two MCP timing detectors to be 157 ps (FWHM) for ²⁴¹Am radiation source, implying that the intrinsic time resolution is about 110 ps (FWHM) for a single timing detector. Thermal-neutron-induced fission of ²³⁵U was studied at the In-hospital Neutron Irradiator (IHNI). An event-by-event energy loss addback technique was developed based on Geant4 calculation to minimize the correction error. The first results of mass yield distributions from ²³⁵U(n $_{t h}$ ,f) are reported.
Charged particle detection with the low-cost BPW21 Si Photodiode
2020, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Citation Excerpt :
It may be pointed out that, shape parameters obtained using the silicon PIN photodiode [8] also corroborated reasonably well with the present work (shown in Table 1). Mass-dependent energy calibration has also been carried out using the prescriptions as described in Refs. [7–9] to obtain the fragment energy in terms of its mass and the corresponding pulse height. The energies of light, heavy and symmetric fragments have been estimated.
It has been found that the low cost commercial photodiode BPW21 (P–N Junction Diode) can be used for the detection of charged particles such as alpha particles and fission fragments. Suitability of this photodiode for fission fragments detection has been checked and mass-dependent energy calibration has also been carried out. It indicates that it can be used as a detector for charged particle detection.
Measurements of 252Cf fission product energy loss through thin silicon nitride and carbon foils, and comparison with SRIM-2013 and MCNP6.2 simulations
2019, Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
Gas ionization detectors are very widely used for radiation detection and measurement, but for external sources an entrance window is used which can reduce particle energy. For heavy ions this energy loss can be significant enough to affect measurements and very thin windows, such as those composed of silicon nitride (SiN), may be utilized to minimize this effect. For fission spectroscopy, carbon conversion foils are also common in measurements. In the current work, energy losses were measured for ²⁵²Cf spontaneous fission products passing through thin foils of carbon and of silicon nitride. The foils ranged in from 22.5 to 131.0 µg/cm² for C and from 56.4 to 402.2 μg/cm² for SiN. For comparison, simulations were performed with the TRIM program in SRIM-2013 and with MCNP6.2. To understand calculation differences, effective charge from partial ionization was predicted by several methods and compared with results directly using the Bethe stopping power formula.
Measurements of charge distributions of the fragments in the low energy fission reaction
2013, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
The measurement for charge distributions of fragments in spontaneous fission ²⁵²Cf has been performed by using a unique style of detector setup consisting of a typical grid ionization chamber and a ΔΕ−Ε particle telescope, in which a thin grid ionization chamber served as the ΔΕ-section and the E-section was an Au–Si surface barrier detector. The typical physical quantities of fragments, such as mass number and kinetic energies as well as the deposition in the gas ΔΕ detector and E detector were derived from the coincident measurement data. The charge distributions of the light fragments for the fixed mass number A₂^⁎ and total kinetic energy (TKE) were obtained by the least-squares fits for the response functions of the ΔΕ detector with multi-Gaussian functions representing the different elements. The results of the charge distributions for some typical fragments are shown in this article which indicates that this detection setup has the charge distribution capability of Ζ:ΔΖ>40:1. The experimental method developed in this work for determining the charge distributions of fragments is expected to be employed in the neutron induced fissions of ²³²Th and ²³⁸U or other low energy fission reactions.
Measurement of fission fragments energy loss
2002, Nuclear Instruments and Methods in Physics Research, Section A: Accelerators, Spectrometers, Detectors and Associated Equipment
Fragment mass distribution of fission after incomplete fusion in the reaction 7li (43a mev) + 232th
1998, Nuclear Physics A
Fragment mass distributions of binary fission were measured for the reaction $^{7} Li (43A MeV) +^{232} Th$ in dependence on the linear momentum transfer. The excitation energy ( $E^{∗}$ ) of the compound nuclei produced by incomplete fusion was deduced applying the massive transfer approach and amounted to 57–205 MeV. The analysis procedure avoids distortions due to the acceptance and error correlation. Total fragment masses and single fragment mass dispersions are discussed in terms of $E^{∗}$ , temperature and an effective parameter describing the stiffness against mass asymmetry. Assuming unchanged stiffness, the dispersions at $E^{∗}$ in excess of ≈ 70 MeV are found to be considerably smaller than expected. This behaviour is interpreted as a consequence of the remarkable cooling down of the hot nuclei due to neutron emission before the fragment masses are formed in the course of fission. Agreement with the data is achieved supposing a cooling time of (60 ± 20) × 10⁻²¹ s based on the neutron emission time taken from the statistical model. It is concluded that fission remains a relatively slow process up to excitation energies of about 200 MeV.

View all citing articles on Scopus

View full text

Article preview

Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment

Abstract

References (19)

Nucl. Instr. and Meth.

Nucl. Instr. and Meth.

Nucl. Instr. and Meth.

Nucl. Instr. and Meth.

Nucl. Instr. and Meth.

Nucl. Instr. and Meth.

Phys. Rev.

Phys. Rev.

Cited by (62)

The FFIS spectrometer for determination of fission fragment mass distribution with the energy–velocity method

Charged particle detection with the low-cost BPW21 Si Photodiode

Measurements of <sup>252</sup>Cf fission product energy loss through thin silicon nitride and carbon foils, and comparison with SRIM-2013 and MCNP6.2 simulations

Measurements of charge distributions of the fragments in the low energy fission reaction

Measurement of fission fragments energy loss

Fragment mass distribution of fission after incomplete fusion in the reaction <sup>7</sup>li (43a mev) + <sup>232</sup>th